There has been no really satisfactory manner in which long distances can be effectively run indoors, such as in a typical school gymnasium. In some gymnasiums, an overhead track is disposed above the floor around the walls, being hung from the latter and the ceiling. These are not only expensive to install but they are also not very satisfactory for a number of reasons. First, they are necessarily relatively narrow in width and cannot easily accommodate many runners at the same time. Second, they are curved at the corners and banked in order to enable the runners to maintain speed, whereupon it becomes difficult to keep to a prescribed course through the turns, especially if several runners are competing at once. Third, as a consequence of the latter aspect, the actual distance run can vary significantly during the longer races, depending upon whether the runner is up or down on the banking through a corner, particularly since the straight portions between the corners are relatively short.
Running about the perimeter of the gymnasium floor is even less satisfactory inasmuch as there is no ready means of banking the corners which limits running speeds pretty much to a "jogging" pace. Furthermore, that expedient often interferes with use of the floor for other purposes. Short, straight line "sprint" types of contests, a 20 yard dash, for instance, have sometimes been conducted in gymnasiums but these are hard on the runners, even dangerous, because they must get up to and maintain maximum speed throughout the course and then come to a full stop as soon as possible to avoid colliding with a wall. Even when wall padding or large cushions or bales are placed at the ends of the course, injury can occur. In any event, the proximity of such obstructions must surely sometimes act as a psychological impediment to the runner, causing him to "let up" a bit near the end of his sprint.
Beginning some years prior to the present invention, "races" have sometimes been run on trampolines. This was instigated by the present inventor and is done on a trampoline, otherwise in conventional form, equipped with resilient backstops at the ends of the bed, such as the backstops shown in U.S. Pat. No. 3,339,925. The contestants run back and forth on the trampoline bed between the backstops, using the latter to reverse their direction at each end of the bed. This, not surprisingly, has several serious limitations. In the first place, it is practical only for children because the speed and weight of adults striking the backstops invariably tends to move the entire apparatus around on the floor. In the second place, the resilient suspension of the bed interferes with running in the sense of that on a relatively non-yielding or unsuspended surface. In the third place, the distance between the backstops is too short; even in the case of the largest trampolines it is only about 22 feet and this is simply not enough in order to run or race effectively in the sense that that is done on the ground. And in the fourth place, since the trampoline bed is elevated, there is always the chance of injury. The present invention was conceived in connection with possible modifications of a trampoline to make it more suitable for running "races" but was not actually tried out at the time because no one felt it would be feasible. When finally tried, with two backstops from a trampoline spaced apart on and anchored to a gymnasium floor, it succeeded beyond all expectations. Apparatus was thus provided by which distances of almost any length could be effectively run, by a single runner or by a group of runners competing with each other, within the confines of a typical gymnasium.